A study presented at the recent Miami Breast Cancer Conference supported the role of the Breast Cancer Index (BCI), a molecular test by bioTheranostics, San Diego, for assessing risk of late recurrence and determining which patients with early stage, estrogen receptor-positive (ER+) breast cancer are likely to benefit from extended endocrine therapy. A workshop discussing use of BCI in clinical practice was also held during the conference.

The study included 750 cases submitted for BCI testing that were analyzed to assess the utilization and clinical utility of the test in routine practice. BCI identified a large portion of patients (39%) as having a less than 5% risk of late recurrence and low likelihood of benefiting from extended endocrine therapy, patients who may be adequately treated with 5 years of adjuvant endocrine therapy.


Nicolas Barthelemy, bioTheranostics

The test also identified a population of patients (32%) with a higher risk of recurrence (greater than 5%) and high likelihood of benefiting from extended endocrine therapy, and who may be more appropriate candidates for longer treatment. Results of this retrospective analysis demonstrate the clinical utility of BCI in stratifying patients and identifying those likely to benefit from extended endocrine therapy, while potentially minimizing unnecessary treatment for those women who are unlikely to benefit from extending endocrine therapy beyond 5 years post-diagnosis.

Nicolas Barthelemy, president and CEO of bioTheranostics, says this review demonstrates the real-world use of BCI along various points from the time of breast cancer diagnosis. Only about half of testing was performed around the 5-year hormone treatment anniversary—suggesting utility for managing patient expectations earlier than 5 years and revisiting previous decisions regarding endocrine therapy for patients well past the 5-year anniversary.

“These results reinforce the growing body of evidence demonstrating the clinical utility of Breast Cancer Index in providing actionable information that aids in decisions about which ER+ patients should be considered for extended endocrine therapy,” Barthelemy says. “This is important, as endocrine therapy entails increased risk of major safety issues such as endometrial cancer, uterine sarcoma, and bone fracture, and tolerability issues that can negatively impact a patient’s quality of life, as well as costs associated with monitoring and mitigating side effects. As a result, BCI may bring clarity to an individual patient’s breast cancer journey.”

The poster, “Clinical utilization of Breast Cancer Index, a gene expression-based assay for prediction of late recurrence and benefit from extended endocrine therapy,” was presented on February 26. On February 28, bioTheranostics hosted a workshop titled “The endocrine biomarker: introducing Breast Cancer Index for clinical decision-making in the extended endocrine setting,” featuring oncologist and breast cancer specialist Stephen C. Malamud, MD, of Mount Sinai Beth Israel Hospital, New York.